The present invention relates to the wireless transmissions for monitoring or actuating elements of a motor vehicle, in particular tire pressure, via pressure sensors housed in them and linked by radio to a receiver associated with an onboard computer. Likewise, door locks may be remotely controlled, from a portable transmitter, via a receiver in the vehicle controlling actuators of these locks.
These two receivers represent a certain volume of hardware and thus a certain cost since, in particular, they include consumption-reducing circuits so that, at least when the vehicle is at rest, these receivers do not discharge the battery of the vehicle too rapidly.
EP-671 289A teaches a receiver designed to receive a frame of defined format in which the value of a field specifies whether it is a pressure-measurement or a remote-control message.
DE-197 20 123A teaches an FM or AM demodulating multi-protocol receiver, without giving details on the transmission protocols.
The present invention aims to reduce the volume of radio hardware.
To that end, the invention first of all relates to a receiver for monitoring tire pressure of a motor vehicle, including means for wireless reception of pressure-signal frames configured so as to forward these frames to a processing means configured to also process frames of another type representative of other signals, and frame discrimination means are provided and configured to control in consequence the processing means.
Hence, the receiver is multifunctional and this avoids for multiple specific receivers for the frames of the other signals, serving, for example, for remote control of the door locks.
Advantageously, the receiving means are configured to pass alternately from a standby state to an alert state according to a predetermined cycle, and the discrimination means are configured to discriminate the frames by discrimination of two particular datatransmission frequencies in two respective headers of the frames, with durations at least equal to the cycle.
The receiver may thus pick up a transmission of a header of one or other of the frames when it is in the alert state, and the discrimination means can rapidly determine the processing which is suitable for the rest of the frame.
The invention also relates to a transmitter for wireless remote control of elements of a motor vehicle, for controlling the receiver of the invention, including wireless transmission means and means for control of the transmission means, which are configured to transmit via them a frame of remote-control bits, characterized in that the control means are configured to transmit a frame header with duration at least equal to that of the header of a tire-pressure monitoring TPMS frame.